in mobile communication, communication may occur between a User Equipment (UE for short, which is also referred to as a terminal or a user terminal) and an Application Server (AS for short), or may also occur between two UEs. Communication between two UEs may be forwarded through an AS, or may also occur through an end-to-end IP data stream between two UEs.
In mobile communication, a Packet Service (PS) network provides IP-based data communication. An IP allocation entity is responsible for an IP address of the UE, and all IP data streams need to pass through that IP allocation entity.
FIG. 1 is a diagram of architecture of a UE accessing a packet domain according to the related technology. As shown in FIG. 1, the structure relates to a UE, a UMTS Terrestrial Radio Access Network (UTRAN for short), an Evolved UMTS (E-UTRAN for short), a Serving GPRS Supporting Node (SGSN for short), a Mobile Management Entity (MME for short), a Home Location Register (HLR for short)/Home Subscriber Server (HSS for short), a Serving Gateway (SGW for short), a Packet Data Network Gateway (PGW for short), a Gateway GPRS Supporting Node (GGSN for short) and an AS. Wherein, the PGW and the GGSN are IP allocation entities under the E-UTRAN and UTRAN/GERAN respectively, and the GGSN and the PGW can be collectively referred to as a public data network gateway.
The UE can access to a core network through the UMTS and the E-UTRAN, and after an IP address is allocated to the UE, the UE can implement IP communication with the AS and other terminals. In the process of communication, after passing through the base station, the IP data streams are forwarded to a pubic data network gateway (GGSN/PGW), and then are transmitted to an AS and a target end UE by the GGSN/PGW according to a routing rule. Wherein, the communication from the UE to the base station and from the base station to the pubic data network gateway (GGSN/PGW) is not based on the IP routing rule, and instead, is based on a routing technology of an underlying link. In the whole process, the base station does not perceive information of the IP layer, for example, the base station does not know information such as the IP address, the port of the UE etc.
In such technical background, even though the UEs implement Peer-to-Peer (P2P) communication through the IP under the same base station, the IP data packet also must detour to the public data network gateway (GGSN/PGW) located on an upper layer. Particularly when the public data network gateway (GGSN/PGW) is located in a home network and two UEs which communicate with each other are located in a visited network, such media routing phenomenon is especially true. FIG. 2 illustrates such detour of an IP data stream. In FIG. 2, a communication link between UE1 and UE2 is UE1→eNodeB→SGW→PGW→(a forwarding network)→SGW→eNodeB→UE2. Obviously, it can be seen that the IP data stream from UE1 to UE2 is transmitted from the same base station eNodeB, and returned to the eNodeB after a full circle.
Such phenomenon is more and more prominent with the progress of the mobile broadband. In the evolution of mobile networks, the mobile networks increasingly show the characteristics of broadband network. With the wide application of smart phones, transmission media data streams in the mobile network are more and more frequent. Notably, as the social application and location based communication application are more and more popular, data traffic in the same area (under the same base station, near the range of the base station) is more and more large. Such traffic needs to detour to the public data network gateway (GGSN/PGW) of the core network, which largely increases backhaul bandwidth requirements, increases delay of the IP communication, and also increases burden of the public data network gateway (GGSN/PGW). In addition, as mobile broadband is more and more thorough, the increasing IP data traffic also makes forward higher requirements on the public data network gateway (GGSN/PGW) of the core network.
In order to deal with the requirements of the increased traffic, operators must increase more public data network gateway (GGSN/PGW) devices, but monthly fee per user presents a downtrend, which also makes the investment and profit of the operators more and more out of balance.